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Dynamic Recrystallization Behaviors in Metals and Alloys

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Advanced Materials Characterization".

Deadline for manuscript submissions: closed (10 July 2022) | Viewed by 16779

Special Issue Editor

CNRS emeritus Senior Scientist, Ecole des Mines de Saint-Etienne (SMS), Laboratoire Georges Friedel (CNRS UMR 5307), 158 cours Fauriel, CS 62362, 42023 Saint-Etienne, CEDEX 2, France
Interests: hot deformation of metals; mechanics of heterogeneous materials

Special Issue Information

Dear Colleagues,

The existence of dynamic recrystallization (DRX), i.e., recrystallization occurring during straining, was initially questioned, until the publication of strong mechanical as well as microstructural evidences. In a second step, it was considered by some authors as a mere “laboratory curiosity” rather than an “industrial tool”. However, DRX has now been recognized as the most important physical mechanism associated with hot working of metals and alloys, the understanding of which is key to the optimization of microstructure and mechanical properties.

Although DRX was first imagined to take place exclusively in low to medium stacking fault energy (SFE) materials, it was later shown that high SFE metals, such as ferritic steels or aluminium alloys, also exhibit recrystallization-like microstructure transformations during hot working. In the first case, DRX occurs by nucleation and growth of new grains and has been termed discontinuous DRX (DDRX); in the second case, DRX results from the progressive “fragmentation” of the initial grains and is often referred to as continuous DRX (CDRX).

The aim of this Special Issue of Materials is to present original reviews on this wide topic and address a number of still open or poorly understood problems, such as DRX in alloys (influence of solutes or precipitates, behavior of two phase alloys), the possible transitions between CDRX and DDRX in some metals, the static microstructure changes after DDRX or CDRX, the influence of strain rate and/or temperature changes during hot deformation, etc.

Theoretical (analytical and/or numerical) as well as experimental contributions are welcome, including papers oriented towards industrial applications.

Prof. Dr. Frank Montheillet
Guest Editor

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Keywords

  • hot working
  • recrystallization
  • microstructure
  • modeling

Published Papers (10 papers)

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Editorial

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3 pages, 834 KiB  
Editorial
Dynamic Recrystallization Behaviours in Metals and Alloys
by Frank Montheillet
Materials 2023, 16(3), 976; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16030976 - 20 Jan 2023
Viewed by 1026
Abstract
The existence of dynamic recrystallization (DRX), i [...] Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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Research

Jump to: Editorial

17 pages, 8209 KiB  
Article
Effect of Hot Working Parameters on Microstructure and Texture Evolution of Hot-Deformed Zr-45Ti-5Al-3V Alloy
by Yuanyuan Lei, Ya Yang, Yuanbiao Tan, Wenwei Zhang, Shanshan Wu and Min Ma
Materials 2022, 15(4), 1382; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15041382 - 13 Feb 2022
Cited by 1 | Viewed by 1084
Abstract
The effect of hot working parameters on the microstructure and texture evolution of the hot-deformed Zr-45Ti-5Al-3V alloy was studied by the electron backscatter diffraction (EBSD) technique. It was found that a high density of dislocations were generated when the alloy was deformed at [...] Read more.
The effect of hot working parameters on the microstructure and texture evolution of the hot-deformed Zr-45Ti-5Al-3V alloy was studied by the electron backscatter diffraction (EBSD) technique. It was found that a high density of dislocations were generated when the alloy was deformed at 700 °C/0.001 s−1 and 800 °C/1 s−1. With the increment in hot-deformation temperature and the decrease in strain rate, the dislocation density decreased due to the increase in dynamic recrystallization (DRX) degree. The discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) mechanisms co-existed during the hot working of the Zr-45Ti-5Al-3V alloy at a true strain of 0.7. The texture evolution of the alloy during hot working was characterized and the texture component mainly consisted of {001}<100>, {011}<100>, {110}<112>, and {112}<110> textures. The volume fractions of {001}<100> and {011}<100> textures obviously rose with the reduction in strain rate, whereas those of {110}<112> and {112}<110> textures gradually decreased. At a given strain rate, an increase trend in the volume fraction of the {001}<100> texture was observed with rising hot-deformation temperature, while the volume fraction of the {011}<100> texture first increased and then decreased. An opposite trend was visible in the {112}<110> and {110}<112> texture compared with {011}<100> textures. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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13 pages, 5579 KiB  
Article
Peculiarities of DRX in a Highly-Alloyed Austenitic Stainless Steel
by Pavel Dolzhenko, Marina Tikhonova, Rustam Kaibyshev and Andrey Belyakov
Materials 2021, 14(14), 4004; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14144004 - 17 Jul 2021
Cited by 7 | Viewed by 1645
Abstract
The features of discontinuous dynamic recrystallization (DRX) in a highly-alloyed austenitic stainless steel were studied at temperatures of 800 °C to 1100 °C. Hot deformation accompanied by DRX was characterized by an activation energy of 415 kJ/mol. The frequency of the sequential DRX [...] Read more.
The features of discontinuous dynamic recrystallization (DRX) in a highly-alloyed austenitic stainless steel were studied at temperatures of 800 °C to 1100 °C. Hot deformation accompanied by DRX was characterized by an activation energy of 415 kJ/mol. The frequency of the sequential DRX cycles depended on the deformation conditions; and the largest fraction of DRX grains with small grain orientation spread below 1° was observed at a temperature of around 1000 °C and a strain rate of about 10−3 s−1. The following power law relationships were obtained for DRX grain size (DDRX) and dislocation density (ρ) vs. temperature-compensated strain rate (Z) or peak flow stress (σP): DDRX ~ Z−0.25, ρ ~ Z0.1, σP ~ DDRX−0.9, σP ~ ρ1.4. The latter, i.e., σP ~ ρ1.4, was valid in the flow stress range below 300 MPa and changed to σP ~ ρ0.5 on increasing the stress. The obtained dependencies suggest a unique power law function between the dislocation density and the DRX grain size with an exponent of −0.5. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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13 pages, 9454 KiB  
Article
Microstructural Evolutions of 2N Grade Pure Al and 4N Grade High-Purity Al during Friction Stir Welding
by Tomoya Nagira, Xiaochao Liu, Kohasaku Ushioda and Hidetoshi Fujii
Materials 2021, 14(13), 3606; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14133606 - 28 Jun 2021
Cited by 12 | Viewed by 1464
Abstract
The grain refinement mechanisms along the material flow path in pure and high-purity Al were examined, using the marker insert and tool stop action methods, during the rapid cooling friction stir welding using liquid CO2. In pure Al subjected to a [...] Read more.
The grain refinement mechanisms along the material flow path in pure and high-purity Al were examined, using the marker insert and tool stop action methods, during the rapid cooling friction stir welding using liquid CO2. In pure Al subjected to a low welding temperature of 0.56Tm (Tm: melting point), the resultant microstructure consisted of a mixture of equiaxed and elongated grains, including the subgrains. Discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and geometric dynamic recrystallization are the potential mechanisms of grain refinement. Increasing the welding temperature and Al purity encouraged dynamic recovery, including dislocation annihilation and rearrangement into subgrains, leading to the acceleration of CDRX and inhibition of DDRX. Both C- and B/B^-type shear textures were developed in microstructures consisting of equiaxed and elongated grains. In addition, DDRX via high-angle boundary bulging resulted in the development of the 45° rotated cube texture. The B/B^ shear texture was strengthened for the fine microstructure, where equiaxed recrystallized grains were fully developed through CDRX. In these cases, the texture is closely related to grain structure development. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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16 pages, 2080 KiB  
Article
Influence of Boundary Migration Induced Softening on the Steady State of Discontinuous Dynamic Recrystallization
by Frank Montheillet
Materials 2021, 14(13), 3531; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14133531 - 24 Jun 2021
Cited by 3 | Viewed by 1259
Abstract
During discontinuous dynamic recrystallization (DDRX), new dislocation-free grains progressively replace the initially strain-hardened grains. Furthermore, the grain boundary migration associated with dislocation elimination partially opposes strain hardening, thus adding up to dynamic recovery. This effect, referred to as boundary migration induced softening (BMIS) [...] Read more.
During discontinuous dynamic recrystallization (DDRX), new dislocation-free grains progressively replace the initially strain-hardened grains. Furthermore, the grain boundary migration associated with dislocation elimination partially opposes strain hardening, thus adding up to dynamic recovery. This effect, referred to as boundary migration induced softening (BMIS) is generally not accounted for by DDRX models, in particular by “mean-field” approaches. In this paper, BMIS is first defined and then analyzed in detail. The basic equations of a grain scale DDRX model, involving the classical Yoshie–Laasraoui–Jonas equation for strain hardening and dynamic recovery and including BMIS are described. A steady state condition equation is then used to derive the average dislocation density and the average grain size. It is then possible to assess the respective influences of BMIS and dynamic recovery on the strain rate sensitivity, the apparent activation energy, and the relationship between flow stress and average grain size (“Derby exponent”) of the material during steady state DDRX. Finally, the possible influence of BMIS on the estimation of grain boundary mobility and nucleation rate from experimental data is addressed. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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14 pages, 7007 KiB  
Article
Hot Deformation and Dynamic Recrystallisation Behaviour of Twin-Roll Cast Mg-6.8Y-2.5Zn-0.4Zr Magnesium Alloy
by Madlen Ullmann, Kristina Kittner and Ulrich Prahl
Materials 2021, 14(2), 307; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14020307 - 08 Jan 2021
Cited by 10 | Viewed by 1462
Abstract
In this work, the deformation behaviour of a twin-roll cast (TRC) Mg-6.8Y-2.5Zn-0.4Zr alloy during plane strain compression was characterised by high-temperature testing. Based on the experimental data, the values of strain-rate sensitivity, the efficiency of power dissipation and the instability parameter were investigated [...] Read more.
In this work, the deformation behaviour of a twin-roll cast (TRC) Mg-6.8Y-2.5Zn-0.4Zr alloy during plane strain compression was characterised by high-temperature testing. Based on the experimental data, the values of strain-rate sensitivity, the efficiency of power dissipation and the instability parameter were investigated under the conditions of various hot deformation parameters. In contrast to conventionally cast material, no lamellae of the LPSO (long period stacking ordered) phase were precipitated in the magnesium matrix after TRC. The precipitation of fine lamellar LPSO phases only occurred during cooling to forming temperature after the heat treatment. Dynamic recrystallization (DRX) hardly occurred during deformation at temperatures between 350 °C and 400 °C. This can be attributed to the precipitation of the lamellar LSPO phases, which contribute to retardation of the DRX process. At higher deformation temperatures and strain rates DRX is pronounced and the twin-induced (TRDX) as well as continuous dynamic recrystallization could be identified as the dominant softening mechanisms. The processing maps were established by superimposing the instability map over the power dissipation map, this being associated with microstructural evolution analysis in the hot deformation processes. Two instability zones could be recognised for the twin-roll cast and heat-treated Mg-6.8Y-2.5Zn-0.4Zr alloy: (1) 350 °C to 460 °C and 0.01 s−1 to 0.3 s−1 and (2) 485 °C to 525 °C and 2.5 s−1 to 10 s−1, where deformation is not favourable. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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30 pages, 13287 KiB  
Article
Improved Predictability of Microstructure Evolution during Hot Deformation of Titanium Alloys
by Ricardo Henrique Buzolin, Franz Miller Branco Ferraz, Michael Lasnik, Alfred Krumphals and Maria Cecilia Poletti
Materials 2020, 13(24), 5678; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13245678 - 12 Dec 2020
Cited by 13 | Viewed by 2146
Abstract
Two different mesoscale models based on dislocation reactions are developed and applied to predict both the flow stress and the microstructure evolution during the hot deformation of titanium alloys. Three distinct populations of dislocations, named mobile, immobile, and wall dislocations, describe the microstructure, [...] Read more.
Two different mesoscale models based on dislocation reactions are developed and applied to predict both the flow stress and the microstructure evolution during the hot deformation of titanium alloys. Three distinct populations of dislocations, named mobile, immobile, and wall dislocations, describe the microstructure, together with the crystal misorientation and the densities of boundaries. A simple model consisting of production and recovery terms for the evolution of dislocations is compared with a comprehensive model that describes the reactions between different type of dislocations. Constitutive equations connect the microstructure evolution with the flow stresses. Both models consider the formation of a high angle grain boundary by continuous dynamic recrystallization due to progressive lattice rotation. The wall dislocation density evolution is calculated as a result of the subgrain size and boundary misorientation distribution evolutions. The developed models are applied to two near-β titanium alloys, Ti-5553 and Ti-17, and validated for use in hot compression experiments. The differences in the predictability between the developed models are discussed for the flow stress, dislocation densities and microstructure evolutions. Only the comprehensive model can predict the different reactions and their contributions to the evolution of mobile and immobile dislocation densities. The comprehensive model also allows for correlating the elastic strain rate with the softening and hardening kinetics. Despite those differences, the selection of the model used has a small influence on the overall prediction of the subgrain size and the fraction of high angle grain boundaries. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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14 pages, 8967 KiB  
Article
Microstructure and Texture Evolution of Mg-Gd-Y-Zr Alloy during Reciprocating Upsetting-Extrusion
by Guoqin Wu, Jianmin Yu, Leichen Jia, Wenlong Xu, Beibei Dong, Zhimin Zhang and Biying Hao
Materials 2020, 13(21), 4932; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13214932 - 03 Nov 2020
Cited by 12 | Viewed by 1674
Abstract
Reciprocating Upsetting-Extrusion (RUE) deformation process can significantly refine the grains size and weaken the basal plane texture by applying a large cumulative strain to the alloy, which is of great significance to weaken the anisotropy of magnesium (Mg) alloys and increase the application [...] Read more.
Reciprocating Upsetting-Extrusion (RUE) deformation process can significantly refine the grains size and weaken the basal plane texture by applying a large cumulative strain to the alloy, which is of great significance to weaken the anisotropy of magnesium (Mg) alloys and increase the application range. In this paper, the Mg-8.27Gd-3.18Y-0.43Zr (wt %) alloy was subjected to isothermal multi-passes RUE. The microstructure and texture evolution, crystal orientation-dependent deformation mechanism of the alloy after deformation were investigated. The results clearly show that with the increase of RUE process, the grains are significantly refined through continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) mechanisms, the uniformity of the microstructure is improved, and the texture intensity is reduced. At the same time, a large number of particle phases are dynamically precipitated during the deformation process, promoting grain refinement by the particle-stimulated nucleation (PSN) mechanism. The typical [10-10] fiber texture is produced after one pass due to the basal plane of the deformed grains with a relatively high proportion is gradually parallel to the ED during extrusion process. However, the texture concentration is reduced compared with the traditional extrusion deformation, indicating that the upsetting deformation has a certain delay effect on the subsequent extrusion texture generation. After three or four passes deformation, the grain orientation is randomized due to the continuous progress of the dynamic recrystallization process. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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18 pages, 8848 KiB  
Article
High-Temperature Deformation Behavior and Microstructural Characterization of Ti-35421 Titanium Alloy
by Danying Zhou, Hua Gao, Yanhua Guo, Ying Wang, Yuecheng Dong, Zhenhua Dan and Hui Chang
Materials 2020, 13(16), 3623; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13163623 - 16 Aug 2020
Cited by 13 | Viewed by 2033
Abstract
A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with [...] Read more.
A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with a strain rate range of 0.01–10 s−1 in this study. Electron backscatter diffraction (EBSD) was used to characterize the microstructure prior to and post hot deformation. The results show that the stress–strain curves have obvious yielding behavior at a high strain rate (>0.1 s−1). As the deformation temperature increases and the strain rate decreases, the α phase content gradually decreases in the α + β phase region. Meanwhile, spheroidization and precipitation of α phase are prone to occur in the α + β phase region. From the EBSD analysis, the volume fraction of recrystallized grains was very low, so dynamic recovery (DRV) is the dominant deformation mechanism of Ti-35421 alloy. In addition to DRV, Ti-35421 alloy is more likely to occur in continuous dynamic recrystallization (CDRX) than discontinuous dynamic recrystallization (DDRX). Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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12 pages, 10573 KiB  
Article
The Role of Long Period Stacking Ordered Phase in Dynamic Recrystallization of a Mg–Gd–Y–Zn–Zr Alloy during Multi-Directional Forging Process
by Huiling Liu, Yingze Meng, Huisheng Yu, Wenlong Xu, Siyang Zhang, Leichen Jia and Guoqin Wu
Materials 2020, 13(15), 3290; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13153290 - 24 Jul 2020
Cited by 9 | Viewed by 2001
Abstract
The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results [...] Read more.
The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results showed that multi-directional forging can effectively refine the grain with the DRX fraction increased, and DRXed grains lead to the decrease of the texture intensity, which can significantly improve the mechanical properties of the alloy. The different morphologies of the LPSO phase have different degrees of promotion relative to DRX behavior. The lamellar LPSO phase with kinks promoted dislocation plugging, where there could be a potential nucleation site for DRX grains. The fragmented lamellar LPSO phase promoted the DRX process through the particle-stimulated nucleation mechanism, and the block-shaped phase was more prone to stress concentration, which promoted DRX. These effects resulted in continuous grain refinement and a more uniform microstructure. Full article
(This article belongs to the Special Issue Dynamic Recrystallization Behaviors in Metals and Alloys)
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